The German electoral system is famously complex, but even given the confusing numbers coming out of Germany, it's clear that Angela Merkel is fantastically popular — and her popularity seems to be growing.

One illuminating picture comes from Die Welt (via Alberto Nardelli), who have compiled a constituency map showing second vote results from 2005, 2009, and 2013 to illustrates "the triumph of Christian Democratic Union [CDU] and Merkel."

To understand the map, you do need to understand a little about how the German election system works, and how it is a mixed proportional and direct electoral system. German voters get two votes — the first to select a Bundestag member in an individual district, and another to vote for a party in general. Roughly half of the Bundestag members are chosen because they were voted in directly, and the other half become Bundestag members through party lists and proportional representation.

Given that the map above only shows the second votes, i.e. the votes for a party in general rather than a specific local leader, it looks like a real sign of the growing endorsement amongst German voters of the conservative agenda of CDU, and Merkel in particular.